Global Measles Resurgence Threatens US, Mexico, and Guatemala's Measles-Free Status

A critical review is underway to determine whether several countries in the Americas, including the United States, Mexico, and Guatemala, continue to meet the criteria for measles elimination. The Regional Monitoring and Re-Verification Commission (RVC) of the Pan American Health Organization (PAHO), an independent panel of international health experts, is currently convening in Washington D.C. to assess the status of countries in the region. This annual conference runs until Friday, with a focus on countries experiencing prolonged measles outbreaks, such as the US and Mexico.

The RVC's role is to advise PAHO, a part of the World Health Organization, on which countries have successfully eliminated measles and rubella. In 2016, the Americas became the first region in the world to eliminate endemic measles transmission following decades of vaccination campaigns. However, a resurgence of the virus has raised concerns, with the US experiencing its largest and deadliest outbreak in nearly 30 years since January 2025.

During this year's review, the commission is examining epidemiological data from 2025 and the first half of 2026 to determine if countries have maintained their elimination status. The US, Mexico, Guatemala, Peru, and Bolivia are at risk of losing their status, following a sharp increase in confirmed measles cases across 17 countries and territories in the Americas between January and October 2026.

The loss of measles elimination status would not trigger immediate consequences but could be considered an embarrassment for the affected countries. Countries that have lost their status in the past, such as Canada last November, have had to dedicate resources to identifying infections, tracing contacts, conducting laboratory tests, isolating patients, and organizing vaccination campaigns. The long-term effects of losing this status could place additional pressure on public health systems.

The RVC's deliberations will conclude on Friday, with the commission making recommendations on the status of individual countries to PAHO Director Jarbas Barbosa, who will make the final determination. The official announcement is expected early next week following the conclusion of the conference. If the US loses its measles elimination status, it would mark a significant step backward from a major public health achievement.